Multi-sector antenna structure

ABSTRACT

A multiple sector cell-site antenna includes a first antenna oriented to serve a first sector, the first antenna electrically connected to a first transceiver group; a second antenna oriented to serve a second sector adjacent to the first sector, the second antenna electrically connected to the first transceiver group; and a single enclosure covering both the first antenna and the second antenna. By providing at least two multiple sector cell-site antennas in a system, the total number of enclosures is reduced while providing redundancy and diversity within the cells.

BACKGROUND OF THE INVENTION

1. Field

Embodiments relate to a multi-sector antenna, a multi-band multi-sectorantenna, and systems including the same.

2. Related Art

In a wireless telecommunications system, a geographic area serviced bythe wireless telecommunications system is divided into spatiallydistinct areas called “cells”. Cells are typically further divided intomultiple ‘sectors’. For example, often each of the cells are dividedinto three equal area sectors. Typically, each cell contains a basetransceiver station (BTS) that uses transceivers (TRXs) and antennas tofacilitate wireless communication between user equipment (UE) and anetwork. The transceivers may include one or more receivers andtransmitters and may be packaged in a Remote Radio Heads (RRHs). A RRHgenerally contains two or more transceivers that are each connected to aduplex filter, thus enabling each transceiver to support simultaneousdownlink transmission and uplink reception via a single antenna.

A BTS may also be referred to as a radio base station (RBS), node B (in3G Networks) or, simply, a base station (BS). Examples of UEs includedevices like mobile phones, computers with wireless Internetconnectivity, and other devices. The network can be any wirelesscommunication network (e.g., GSM, CDMA, etc.).

The antennas may be housed in an enclosure that protects the antennasfrom environmental conditions or conceals the antenna's electronicequipment from public view. The enclosure may be referred to as a“radome”. The enclosure is often constructed of a material that istransparent to radio waves and inhibits icing from accumulating on itssurface. For instance, the enclosure may be made of a fiberglassmaterial.

Basic Antenna

The simplest antenna technology is a single input, single output (SISO)antenna, which refers to a wireless communications system in which oneantenna is used for transmission (e.g., a single ‘input’ into thetransmission channel) and one antenna is used for reception (e.g., asingle ‘output’ out of the transmission channel). The transmissionchannel may be a downlink channel (from the BTS's transmitter(s) to theUE's receiver(s)) or an uplink channel (from the UE's transmitter(s) tothe BTS's receiver(s)). While relatively simple to design, SISO systemsare vulnerable to problems caused by multipath fading effects.

Multipath fading effects result when an electromagnetic field (EM field)meets obstructions such as hills, canyons, buildings, and utility wires,which results in the EM field scattering (reflecting), and thus takingmultiple paths to reach its destination, resulting in random phaseshifts between the multiple signal paths. When a source sends a RadioFrequency (RF) signal that encounters scattering, the recombination ofthe multiple RF paths' signals with various phases causes Rayleighfading effects. When the signals combine into one signal at thereceiving antenna, because the signals are out of phase, the effectivesignal is attenuated. When the attenuation is severe, the signal may bebelow the receiver's minimum discernible signal level, and the receivermay not be able to successfully receive and decode the original signal.In a wireless telecommunications system, such multipath fading can causea reduction in coverage area, a reduction in achievable data speeds andan increase in the number of errors in processing the signal.

Diversity

To avoid multipath fading effects, systems are available to improvesignal quality by using a plurality of antennas in combination withdiversity techniques. Diversity techniques can be used to combine thesignals received from the multiple antennas, drastically reducing theprobability of fading, because both antennas likely will not experiencesimultaneous severe fading attenuation.

Diversity techniques can be used for reception and/or transmissions fromthe multiple antennas. Various terminology is used to describe differentdiversity techniques. For example, a single input, multiple output(SIMO) technique (uplink or downlink) refers to a diversity techniquehaving a single transmitter antenna (single input) and multiplereception antennas (multiple output) (also known as diversity reception)utilizing any number of separate reception antennas. A multiple input,multiple output MIMO technique (uplink or downlink) refers to atechnique including both multiple transmitter antennas (multiple codedtransmission signals) and multiple reception antennas.

The multiple reception antennas may provide two-way diversity orfour-way diversity depending on the number of independent (ordecorrelated) signals provided from the separate antennas.

Each of the multiple antennas used to provide the separate diversesignals can contain multiple antenna elements (e.g., dipole elements).In dipole antennas, a plurality of polarized dipole elements (typically,four to ten elements) are equally spaced and vertically stacked toachieve directivity (antenna gain), thus each antenna may actually be anarray of antenna elements. The dipoles may be arranged such that theantenna is either a linear dipole antenna (one element) or dualslant/cross-polarized dipole antenna (twin elements located together).

FIG. 1 illustrates different linear dipole antenna array arrangements.

As illustrated in FIG. 1, in a linear array of dipole antennas 100, thedipole elements are all of the same polarization. These dipole elementsmay be arranged in an array of vertically polarized dipole elements 110.Alternatively, the dipole elements may be arranged in an array ofhorizontally polarized dipole elements 120. In antenna arrays thatutilize linear arrays of dipole elements, all of the dipole elementsreceive the same polarization and thus having the same fading behavior(e.g., correlated fading statistics). Therefore to achieve sufficientdiversity (independent fading statistics), multiple discrete lineardipole antenna arrays are spaced a distance apart in a technique knownas a space diversity (horizontal spatial separation of the antennas).

In space diversity, the antennas are spaced a sufficient horizontaldistance apart to ensure that the Rayleigh fading that each arrayexperiences will be independent (decorrelated). In more detail, becauseof the different physical location of the arrays, the phases of thesignals traveling different paths that are recombined are differentenough that the apparent fading will be different. However, the minimumdistance required between the antenna arrays to ensure independentfading effects is on the order of seven to ten lambda λ (where λ is thewavelength of the RF signal). This minimum distance between the antennaarrays makes the use of a single integrated structure, such as a radome,to house the two antenna arrays impractical because a structure of suchsize may be visually imposing, heavy and may create a large surface areathat is susceptible to wind loading. Therefore, the installation ofmultiple antenna arrays using spatial diversity generally requiresmultiple structural enclosures (e.g., separate radomes) resulting inincreased costs and more complex installations when compared to singleenclosures.

FIGS. 2A and 2B illustrate a conventional antenna installation utilizingspace diversity.

As illustrated in FIG. 2A, a conventional antenna structure is mountedon a cellular boom 250 to achieve spatial diversity. FIG. 2B is athree-dimensional view of the conventional antenna structure of FIG. 2A.In the conventional antenna structure, to achieve spatial diversity, afirst antenna array 210 a and a second antenna array 210 b are mountedon the face of the cellular boom 250 and separated from each other by adistance D, where the distance D is a distance sufficient to achievesufficient spatial diversity between the two antenna arrays 210/210 b.The required separation distance D (e.g., seven to ten lambda λ), maymake the use of a single integrated structure to house both the firstantenna array 110 a and the second antenna array 110 b impractical.Therefore, in the conventional antenna structure to obtain spatialdiversity, the first antenna array 210 a is protected by a firstenclosure 230 a and the second antenna array 210 b is protected by thesecond enclosure 230 b.

To eliminate the need for spacing between the two antenna arrays, andthus separate enclosures, as required for a diversity scheme thatutilizes linear dipole antennas, while still achieving adequatedecorrelation, cross-polarized dipole antennas may be used.

FIG. 3 illustrates different various cross-polarized antenna arrayarrangements.

As illustrated in FIG. 3, in cross-polarized antennas 300, the elementsthat make up the antenna array are orthogonally polarized in a schemeknown as polarization diversity. In polarization diversity, two-waydiversity is achieved by pairing two complementary polarized antennaelements together into a single structure.

In the cross-polarized antenna array the dual polarized elements may bea dual slant cross polarized antenna 310, in which the polarizedelements cross each other in a slant (e.g., +45 degrees and −45degrees). Alternatively, the array of dual polarized elements may be avertical/horizontal cross polarized antenna 320 in which the polarizedelements cross each other vertically and horizontally. In additional todual-slant and vertical/horizontal cross-polarized antennas, the dualpolarized elements may be arranged to provide circular polarization (notshown). The circular polarization may be either right hand circularpolarization (RHCP) or left hand circular polarization (LHCP). Each ofthe polarized elements in the cross-polarized stack of elements has aport, resulting in the cross-polarized antenna array having two ports(e.g., connections), a first port 340 for one polarization and a secondport 350 for the other polarization. The cross-polarized antennaconfiguration provides two-way diversity without requiring the largespatial separation of the antenna arrays that is required in spatialdiversity. Thus, the two sets of antenna elements may be packagedtogether in one structure, eliminating the requirement for multipleseparate antenna structures.

Dual polarized antennas provide only two-way diversity, because thereare only two orthogonal polarizations. If four-way diversity is desired,a pair of cross-polarized antennas may be required to achieve bothspatial diversity and polarization diversity. The minimum horizontalspacing between the pair of cross-polarized antennas necessary toachieve adequate spatial diversity may again require a system havingmultiple structural enclosures in order to be practical.

SUMMARY OF THE INVENTION

At least one example embodiment relates to a multiple sector cell-siteantenna.

In one embodiment, the multiple sector cell-site antenna includes afirst antenna oriented to serve a first sector, the first antennaelectrically connected to a first transceiver group; a second antennaoriented to serve a second sector adjacent to the first sector and thesecond antenna electrically connected to the first transceiver group;and a single enclosure covering both the first antenna and the secondantenna.

In one embodiment, the first transceiver group is integrated in thesingle enclosure.

In one embodiment, the single enclosure includes antenna input/outputports to connect the first antenna and the second antenna to the firsttransceiver group.

In one embodiment, the first antenna and the second antenna are each anarray of antenna elements.

In one embodiment, the first transceiver group is a Remote Radio Head(RRH) and includes at least four ports, the first antenna is a firstdual-polarized antenna electrically connected to two of the at leastfour ports, and the second antenna is a second dual-polarized antennaelectrically connected to two of the at least four ports.

In one embodiment, the first antenna and the second antenna are each oneof an array of dual-polarized dual-slant antenna elements, an array ofdual-polarized vertical/horizontal dipole antenna elements and an arrayof dual-polarized right-hand/left-hand polarized antenna elements.

In one embodiment, the single enclosure is a radome and the firstantenna and the second antenna meet to form a first corner.

In one embodiment, the multiple sector cell-site antenna includes apivot point located on the enclosure at the first corner, the pivotpoint configured to adjust an angle between the first antenna and thesecond antenna based on a number of sectors in the cell-site.

In one embodiment, the pivot point is configured to incrementally adjustthe angle between one of 120 degrees, 90 degrees and 60 degrees.

At least one example embodiment relates to a multiple sector cell-siteantenna system.

In one embodiment, the multiple sector cell-site antenna system includesa first multiple sector cell-site antenna and a second multiple sectorcell-site antenna. The first multiple sector cell-site antenna includesa first antenna oriented to serve a first sector, the first antennaelectrically connected to a first transceiver group; a second antennaoriented to serve a second sector, the second sector adjacent to thefirst sector, the second antenna electrically connected to the firsttransceiver group; and a first enclosure covering both the first antennaand the second antenna. The second multiple sector cell-site antennaincludes a third antenna oriented to serve the first sector, the thirdantenna electrically connected to a second transceiver group; a fourthantenna oriented to serve a third sector, the fourth antennaelectrically connected to the second transceiver group; and a secondenclosure covering both the third antenna and the fourth antenna.

In one embodiment, the first transceiver group is integrated in thefirst enclosure and the second transceiver group is integrated in thesecond enclosure.

In one embodiment, the first enclosure includes antenna input/outputports configured to connect the first antenna and the second antenna tothe first transceiver group and the second enclosure includes antennainput/output ports to connect the third antenna and the fourth antennato the second transceiver group.

In one embodiment, each of the antennas are an array of antennaelements.

In one embodiment, the first multiple sector cell-site antenna and thesecond multiple sector cell-site antenna are spatially separated by adistance such that spatial diversity against fading is provided for thefirst sector.

In one embodiment, the first transceiver group is a first Remote RadioHead (RRH) and the second transceiver group is a second RRH and each RRHeach include at least four ports. The first antenna is a first polarizedantenna electrically connected to two of the at least four ports of thefirst RRH and the second antenna is a second polarized antennaelectrically connected to two of the at least four ports of the firstRRH. The third antenna is a third polarized antenna electricallyconnected to two of the at least four ports of the second RRH and thefourth antenna is a fourth polarized antenna electrically connected totwo of the at least four ports of the second RRH.

In one embodiment, the first antenna that is connected to the firsttransceiver group and third antenna that is connected to the secondtransceiver group together utilize antenna cross connect to provideredundancy and diversity to the first sector.

In one embodiment, the first antenna and second antenna meet to form afirst corner and the third antenna and fourth antenna meet to form asecond corner. The first enclosure includes a first pivot point at thefirst corner, the first pivot point configured to adjust an anglebetween the first antenna and the second antenna based on a number ofsectors in the cell-site. The second enclosure includes a second pivotpoint at the second corner, the second pivot point configured to adjustan angle between the third antenna and the fourth antenna based on thenumber of sectors in the cell-site.

At least one example embodiment relates to multiple-band multiple-sectorcell-site antenna.

In one embodiment, the multiple-band multiple-sector cell-site antennaincludes a first high-band antenna, a second high-band antenna, a firstlow-band antenna and a single enclosure covering the first high-bandantenna, the second high-band antenna, and the first low-band antenna.The first high-band antenna is configured to utilize a first radio waveband and oriented to serve a first sector, the first high-band antennaelectrically connected to a first high-band transceiver group. Thesecond high-band antenna is configured to utilize the first radio waveband and oriented to serve a second sector adjacent to the first sector,the second high-band antenna electrically connected to the firsthigh-band transceiver group. The first low-band antenna configured toutilize a low radio wave band and oriented to serve the first sector,the low-band antenna electrically connected to a low-band transceivergroup.

In one embodiment, each of the antennas are an array of dual-polarizedantenna elements that provide two-way diversity for one or more ofuplink reception of signals and downlink transmission of signals.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given herein below and the accompanying drawings,wherein like elements are represented by like reference numerals, whichare given by way of illustration only and thus are not limiting of thepresent invention and wherein:

FIG. 1 illustrates different linear dipole antenna array arrangements.

FIGS. 2A and 2B illustrate a conventional antenna installation utilizingspace diversity.

FIG. 3 illustrates different cross-polarized antenna array arrangements.

FIG. 4A illustrates a multi-sector antenna structure utilizing antennacross connect according to an example embodiment.

FIG. 4B illustrates a multi-sector antenna structure having dual-portcross-polarized antennas according to an example embodiment.

FIG. 5A illustrates a system containing at least two multi-sectorantenna structures configured to achieve two-way diversity according toan example embodiment.

FIG. 5B illustrates a system containing at least two multi-sectorantenna structures configured to achieve four-way diversity according toan example embodiment.

FIG. 6 illustrates a multi-band multi-sector antenna structure accordingto an example embodiment.

FIG. 7 illustrates an example embodiment of a system containing at leasttwo multi-band multi-sector structures according to an exampleembodiment.

FIG. 8 illustrates a multiple sector cell-site antenna installation thatis configured to serve four (4) sectors by utilizing multiple multi-bandmulti-sector antenna structures.

FIG. 9 illustrates a multiple sector cell-site antenna installation thatis configured to serve six (6) sectors by utilizing multiple multi-bandmulti-sector antenna structures.

It should be noted that these Figures are intended to illustrate thegeneral characteristics of methods, structure and/or to merelyillustrate the certain example embodiments and to supplement the writtendescription provided below. These drawings are architectural blockdiagrams of the system, and are not, however, to scale and may notprecisely reflect the precise structural or mechanical characteristicsof any given embodiment, and should not be interpreted as defining orlimiting the range of values or properties encompassed by exampleembodiments. For example, the relative sizesand positioning of thearrays, and/or structural elements may be reduced or exaggerated forclarity. The use of similar or identical reference numbers in thevarious drawings is intended to indicate the presence of a similar oridentical element or feature.

DETAILED DESCRIPTION OF THE EMBODIMENTS

While example embodiments are capable of various modifications andalternative forms, embodiments thereof are shown by way of example inthe drawings and will herein be described in detail. It should beunderstood, however, that there is no intent to limit exampleembodiments to the particular forms disclosed, but on the contrary,example embodiments are to cover all modifications, equivalents, andalternatives falling within the scope of the claims. Like numbers referto like elements throughout the description of the figures.

Methods discussed below may be implemented by hardware, software,firmware, middleware, microcode, hardware description languages, or anycombination thereof. When implemented in software, firmware, middlewareor microcode, the program code or code segments to perform the necessarytasks may be stored in a machine or computer readable medium such as astorage medium. A processor(s), Field Programmable Gate Array (FGPA) oran Application Specific Integrated Circuit (ASIC) may perform thenecessary tasks.

Specific structural and functional details disclosed herein are merelyrepresentative for purposes of describing example embodiments of thepresent invention. This invention may, however, be embodied in manyalternate forms and should not be construed as limited to only theembodiments set forth herein.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of example embodiments. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” when usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedconcurrently or may sometimes be executed in the reverse order,depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, e.g., those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Portions of the example embodiments and corresponding detaileddescription are presented in terms of software, or algorithms andsymbolic representations of operation on data bits within a computermemory. These descriptions and representations are the ones by whichthose of ordinary skill in the art effectively convey the substance oftheir work to others of ordinary skill in the art. An algorithm, as theterm is used here, and as it is used generally, is conceived to be aself-consistent sequence of steps leading to a desired result. The stepsare those requiring physical manipulations of physical quantities.Usually, though not necessarily, these quantities take the form ofoptical, electrical, or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

In the following description, illustrative embodiments will be describedwith reference to acts and symbolic representations of operations (e.g.,in the form of flowcharts) that may be implemented as program modules orfunctional processes include routines, programs, objects, components,data structures, etc., that perform particular tasks or implementparticular abstract data types and may be implemented using existinghardware at existing network elements. Such existing hardware mayinclude one or more Central Processing Units (CPUs), digital signalprocessors (DSPs), application-specific-integrated-circuits, fieldprogrammable gate arrays (FPGAs) computers or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise, or as is apparent from the discussion,terms such as “processing” or “computing” or “calculating” or“determining” of “displaying” or the like, refer to the action andprocesses of a computer system, or similar electronic computing device,that manipulates and transforms data represented as physical, electronicquantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission or display devices.

Note also that the transmission medium may be twisted wire pairs,coaxial cable, optical fiber, or some other suitable transmission mediumknown to the art. The example embodiments not limited by these aspectsto any given implementation.

In one or more example embodiments, a structural enclosure includes atleast two antennas that are each configured to serve two adjacentseparate sectors from one common location, for example, from a ‘corner’where two adjacent sectors meet. A system including an arrangement of atleast two structural enclosures provides diversity and redundancy, whilereducing the total number of structural enclosures by at least half incomparison to a conventional arrangement, thus reducing cost andinstallation complexity.

FIG. 4A illustrates a multi-sector antenna structure utilizing AntennaCross Connect (ACC) according to an example embodiment.

In FIG. 4A, a multi-sector antenna structure 400 includes at least afirst antenna 410, a second antenna 420, a structural enclosure 430, afirst transceiver group (e.g., a set of transceivers) within an RRH 440and a cellular boom 450. The first antenna 410 may be an array of firstelements and the second antenna 420 may be an array of second elements.The antennas are configured to provide both downlink transmission anduplink reception of signals to and from at least two adjacent sectorsfrom one common location using the RRH 440, for example, from a ‘corner’where the two adjacent sectors meet. Rather than arranging the antennaarrays to face a same direction and serve the same sector, the at leasttwo antenna arrays 410/420 are each configured to serve a differentsector by arranging the arrays to serve the sectors from the ‘corners’,with each array pointed differently to serve one of the at least twoadjacent sectors. For example, the first antenna array 410 faces (andserves) Sector 1 and the second antenna array 420 faces (and serves)Sector 2.

The RRH 440 includes a first transceiver group (e.g., a plurality ofreceivers and transmitters) (not shown). The receivers convert receivedsignals from RF signals to digital signals that are conveyed to aBase-Band Unit (BBU) (not shown) over a Common Public Radio Interface(CPRI). The digital signals are often optic signals and the BBU is oftenlocated a significant distance from the RRH 440. Likewise, thetransmitters transmit radio frequency (RF) signals conveyed from the BBUto user equipments (UEs) (not shown) located within the sector. The RRH440 may include one or more transceivers.

Antenna Cross Connect

Conventionally, each RRH controls transmission and reception within thesector from one or more antennas. However, failure of an RRH may resultin a signal outage within the sector. In contrast, as shown in FIGS. 4Aand 4B, in one or more example embodiments the RRH 440 is connected toantenna arrays that serve different sectors, namely the first antennaarray 410 serving Sector 1 and the second antenna array 420 servingSector 2 in a scheme known as Antenna Cross Connect (ACC). In ACC,multiple RRHs are connected to antennas used to support adjacentsectors. Thus, if any one RRH fails, there remains RRHs and antennasthat can continue to serve the sector. Thus, while coverage may bedegraded because of the loss of multiple antennas per sector (loss ofdiversity reception or MIMO transmission), coverage is not completelylost.

The antenna arrays 210/220 may be single port linear antenna arrays (forSISO uplink reception or SIMO downlink transmission). For instance, eachof the antenna arrays 210/220 may be an antenna array 110 or an antennaarray 120 as illustrated in FIG. 1.

Likewise, the antenna arrays may be dual polarization dual port antennasin which cross-polarized antennas are used at the BS for uplinkreception from the sector of interest or downlink transmission to thesector of interest. For instance, each of the antenna arrays may havecross-polarized antenna elements 310 or 320, as illustrated in FIG. 3.

FIG. 4B illustrates a multi-sector antenna structure 400-b havingdual-port cross-polarized antennas according to an example embodiment.

As illustrated in FIG. 4B, the antenna structure 400-b has a samestructure as the multi-sector antenna structure 400 except the antennaarrays 410-b/420-b are dual-port cross-polarized antennas where eachantenna array 410-b/420-b is a pair of cross-polarized antenna arrays,resulting in the RRH 440-b being connected to each antenna array410-b/420-b via a pair of electrical connections. Therefore, while theRRH 440 of FIG. 4A is shown connected to each of the antenna arrays410/420 via a single connection, the RRH 440-b in FIG. 4B is connectedto each of the antenna arrays 410-b/4200 b via a pair of electricalconnections, one for each array of the polarized antenna elements in theantenna array. By utilizing cross-polarized antennas, two-way diversitycan be achieved from each antenna structure 400-b by pairing twocomplementary polarized antenna elements together in a single antenna.Because the multi-sector antenna structure 400-b is a dual-portcross-polarized antenna, the multi-sector antenna structure 400-b maysupport two antenna port connections.

The structural enclosure 430 may be made of a material that istransparent to the RF signals and has mechanical properties making theenclosure substantially strong, waterproof and resistant to icing. Insome example embodiments, the RRH 440 may be external to the structuralenclosure 430 and therefore the structural enclosure 430 may includeports on the surface thereof to connect the RRH 440. In other exampleembodiments, the structural enclosure 430 may have the RRH 440integrated therein. The shape of the structural enclosure may bedictated by the design of the cell, such as whether the cell is a3-sector, 4-sector, or 6-sector cell and whether the structuralenclosure 430 has the RRH 440 integrated therein.

FIGS. 5A and 5B illustrate systems containing at least two multi-sectorantenna structures according to example embodiments.

As shown in FIG. 5A, a system 500 may include a cellular boom 550, atleast a first multi-sector antenna structure 500 a and a secondmulti-sector antenna structure 500 b mounted thereto. Each of themulti-sector antenna structures 500 a/500 b has a same structure as themulti-sector antenna structure 400. For instance, each of themulti-sector antenna structures 500 a/500 b contains at least twoantenna arrays that each serve separate adjacent sectors and are bothconnected to the same RRH (e.g. transceiver group). Therefore, the firstmulti-sector antenna structure 500 a includes a first RRH 540 a thatsimultaneously serves at least a first sector (Sector 1) via a firstantenna array 510 a and a second sector (Sector 2) via a second antennaarray 520 a. Likewise, the second multi-sector antenna structure 500 bincludes a second RRH 540 b that simultaneously serves at least thefirst sector via a first antenna 520 b and a third sector via a secondantenna 510 b. If the signals are conveyed appropriately to the BaseBand Unit (BBU) using ACC, each sector is served by at least two RRHs.For example, the first sector (Sector 1) is served by antenna 510 aconnected to RRH 540 a, and by antenna 520 b connected to RRH 540 b.

Each RRH can transmit/receive appropriate signals to/from two adjacentsectors. This results in each sector being served by at least two RRHs,thus providing redundancy in each of the sectors. For instance, thefirst sector is being served by RRH 540 a and RRH 540 b.

Additionally, two way diversity may be achieved upstream at the BBU, ifeach of the at least two multi-cell antenna structures 500 a/500 b aresufficiently spaced a horizontal distance D (e.g., seven to ten lambdaλ). In contrast to the conventional example of spatial diversityillustrated in FIG. 2A, in the example embodiment illustrated in FIG.5A, spatial diversity can be achieved while minimizing the size and thenumber of structural enclosures 530 a/530 b.

Likewise, if the antenna arrays in each of the at least two multi-cellantenna structures are cross-polarized antennas, polarization diversitymay be provided to each sector. Thus, providing four receive signalsand/or four transmit signals (depending on whether the antennas are SIMOor MIMO) resulting in four-way diversity.

FIG. 5B illustrates a system 500-2 containing at least two multi-sectorantenna structures configured to achieve four-way diversity according toan example embodiment.

As illustrated in FIG. 5B, a system 500-2 has the same structure as thesystem 500 except, the system 500-2 contains multi-cell antennastructures 500 a-2/500 b-2, which in addition to being sufficientlyspaced to achieve spatial diversity, each include cross-polarizedantennas. By including cross-polarized antennas in the system 500-2four-way diversity may be achieved upstream at the BBU (not shown).

As illustrated in FIG. 5B, the multi-cell antenna structures 500 a-2/500b-2 have the same structure as the multi-cell antenna structures 500a/500 b illustrated in FIG. 5A except that the multi-cell antennastructures 500 a-2/500 b-2 antenna's may have the antenna structureillustrated in FIG. 4B, where each antenna array is a pair ofcross-polarized antenna elements and the RRHs 540 a-2/540 b-2 are eachconnected to respective antenna arrays via a pair of electricalconnections. Thus, each RRH 540 a-2/540 b-2 has two pairs of portsconnected a respective one of the antenna structures 500 a-2/500 b-2.Thus four-way diversity can be achieved in each sector by creatingspatial diversity between a pair of cross-polarized antennas.

Additional multi-cell antenna structures may be similarly arrangedadjacent to the multi-sector antenna structures (500 a/500 b) in thesystem 500, with half of each additional structure's antennas servingone sector and half serving a next adjacent sector.

In the aforementioned systems having at least two multi-sector antennastructures, each sector is served by multiple RRHs, and each RRH servesmultiple adjacent sectors. This configuration provides both redundancywithin the sector as well as diversity. Redundancy is achieved becausefailure of any one RRH will impact two adjacent sectors, but due to thecross-connection, each sector will still have at least half of itsantennas served by the remaining operable RRH. Further, diversity may beachieved if the multi-sector structures are spaced properly to providespatial diversity and/or each structure includes antennas that utilizecross-polarized elements. If the multi-sector structures are spacedproperly to provide spatial diversity and each structure includesantennas that utilize cross-polarized elements then four-way diversitymay be achieved. Further, since each multi-sector structure serves atleast two sectors, the total number of structural enclosures is reducingby half, thus reducing cost and installation complexity while providingredundancy and diversity.

FIG. 6 illustrates a multi-band multi-sector antenna structure accordingto an example embodiment.

As shown in FIG. 6, the multi-band multi-sector antenna structure 600includes at least a first high-band antenna 610, a low band antenna 615,a second high-band antenna 620 and a structural enclosure 630. Themulti-band multi-sector antenna 600 may be mounted on a cellular boom650. The first and second high-band antennas (610/620) have the samestructure as the first antenna 410 and second antenna 420 and may beconfigured to serve 1,850-1,990 Mhz, also known as PersonalCommunications Service (PCS) band and Advanced Wireless Services (AWS)band. For instance, the first and second high-band antennas (610/620)are configured for both downlink transmission (to the UEs) and uplinkreception of signals (from the UEs) in the high-band to support twoadjacent sectors from one common location using a high band transceiver(640), for example, from a ‘corner’ where the two adjacent sectors meet.

The low-band antenna 615 may be configured to serve 698-894 MHz. Thelow-band antenna 615 is configured to provide both downlink transmission(to the UEs) and uplink reception (from the UEs) using signals in thelow band using a low band transceiver 645. The multi-band multi-sectorantenna structure 600 may include a single low-band antenna 615 that iseither a linear dipole antenna or a dual polarization antenna. Thus, themulti-band multi-sector antenna structure 600 may not include low bandelements that face both sectors from the corner, but rather may onlysupport one sector (face) for the low band, because the spatial distancerequired to achieve sufficient diversity in the low-band frequency rangemay make it difficult to achieve spatial diversity. Therefore, eachcorner radome may support one sector (face) for the low band. Bypackaging the low band array along with both high band arrays, thepackaging efficiency is increased, and overall size, weights, and costsare decreased as compared to deploying with separate high band and lowband enclosures.

FIG. 7 illustrates an example embodiment of a system containing at leasttwo multi-band multi-sector structures according to an exampleembodiment.

As shown in FIG. 7, a system 700 may include a cellular boom 750 and atleast a first multi-band multi-sector antenna structure 700 a and asecond multi-band multi-sector antenna structure 700 b mounted thereto.Each of the multi-band multi-sector antenna structures 700 a/700 b has asame structure as the multi-band multi-sector antenna structure 600. Thefirst multi-band multi-sector antenna structure 700 a includes a firsthigh band RRH 740 a that simultaneously serves at least a first sector(Sector 1) via a first high band antenna 710 a and a second sector(Sector 2) via a second high band antenna 720 a. Additionally, the firstmulti-band multi-sector antenna structure 700 a includes a low band RRH745 a that serves one of the first and second sectors (e.g., Sector 1)via a low band antenna 715 a.

The second multi-band multi-sector antenna structure 700 b includes asecond high band RRH 740 b that simultaneously serves at least thesecond sector (Sector 2) via a first high band antenna 710 b and a thirdsector (Sector 3) via a second high band antenna 720 b. Additionally,the second multi-band multi-sector antenna structure 700 b includes alow band RRH 745 b that serves one of the second and third sectors (e.g,Sector 2) via a low band antenna 715 b.

Additional multi-band multi-sector antenna structures may be similarlyarranged in the system 700 adjacent to the at least two multi-bandmulti-sector antenna structures (700 a/700 b), with half of eachstructure's high-band antennas serving one sector and half serving anext adjacent sector.

Therefore, each of the multi-band multi-sector antenna structures 700a/700 b contain at least two high band antenna arrays that each serveseparate adjacent sectors and are both connected to the same high bandRRH. Additionally, each of the multi-band multi-sector antennastructures 700 a/700 b include a low band antenna that serves one of theadjacent sectors and is connected to a low band RRH. If the signals arecorrectly sorted upstream, each high band RRH (740 a/740 b) cantransmit/receive appropriate signals to/from two adjacent sectors andeach low band RRH 745 a/745 b can transmit/receive signals from one ofthe adjacent sectors.

This results in each sector being served by at least two high-band RRHsand at least one low-band RRH, thus providing high-band redundancy andlow band coverage in each of the sectors. For instance, the first sectoris being served by the high-band RRH 740 a, the high-band RRH 740 b andthe low-band RRH 745 a.

Further, if each of the at least two multi-band multi-sector antennastructures 700 a/700 b are sufficiently spaced (e.g., seven to tenlambda λ) the multi-band multi-sector antenna structures 500 a/500 b mayprovide space diversity in the high-band within each sector. Likewise,if the antenna arrays in each of the at least two multi-bandmulti-sector antenna structures 700 a/700 b are cross-polarizedantennas, polarization diversity in both the high-band and the low-bandmay be provided within each sector. If the multi-band multi-sectorstructures are spaced properly to provide spatial diversity and eachstructure 700 a/700 b includes high and antennas that utilizecross-polarized elements then four-way diversity may be achieved in thehigh band. However, in the low band, it is preferable to usepolarization diversity in the low band and not Spatial diversity becauselow band antennas would require a large horizontal spatial separation toget appreciable diversity compared to the diversity achieved with theuse of polarization diversity.

Each of the multi-band multi-sector antenna structures 700 a/700 b mayhave their respective RRHs integrated into the structure. For instance,the first multi-band multi-sector antenna structures 700 a may have thefirst high band RRH 740 b and the first low-band RRH 745 a integrated inan enclosure 730 a. Alternatively, each of the multi-band multi-cellantenna structures (700 a/700 b) may have ports on the surface of theenclosure to externally connect the RRHs thereto.

FIGS. 8 and 9 illustrate example embodiments of a multi-bandmulti-sector antenna structure for use in a cell divided into more than3 sectors.

FIG. 8 illustrates four (4) multi-band multi-sector antenna structures800 a, 800 b, 800 c and 800 d provided on a cellular boom. Thisconfiguration serves a four-sectored cell site where each sector covers90 degrees rather than the 120 degrees covered by each multi-sectorantenna structure in the three-sector cell configuration of FIGS. 1-5.

FIG. 9 illustrates six (6) multi-band multi-sector structures 900 a, 900b, 900 c, 900 d, 900 e and 900 f. This configuration serves asix-sectored cell site where each sector covers 60 degrees. Each of themulti-band multi-cell antenna structures 800 a-d and 900 a-f have thesame internal components as the multi-band multi-cell antenna structure600 illustrated in FIG. 6. For instance, each of the multi-bandmulti-cell antenna structures 800 a-d/900 a-f are configured to servetwo adjacent sectors and may provide antenna cross connect (ACC) betweenRRHs in the two adjacent sectors. The cross connected RRHs may be onlyfor the high-band antennas or may be for both the high-band antennas andthe low-band antennas. Further, the multi-band multi-cell antennastructures 800 a-d/900 a-f may provide high-band spatial diversity, ifthe structures are sufficiently spaced apart (e.g., seven to ten lambdaλ). Likewise, the multi-band multi-cell antenna structures 800 a-d/900a-f may provide high-band polarization diversity, if the high-bandantenna arrays are cross-polarized and/or low band-polarizationdiversity, if the low band antenna arrays are cross-polarized. However,the multi-band multi-cell antenna structures 800 a-d/900 a-f havedifferent angles between the antenna arrays as compared to themulti-band multi-cell antenna structures 800 a-d/900 a-f. The anglebetween the antenna arrays depends on how many sectors the cell isbroken into. In a three (3) sector cell, having three (3) multi-cellantenna structures, such as illustrated in FIGS. 4-7, the angle betweenthe antenna arrays may be 120 degrees. In a four (4) sector cell, havingfour (4) multi-cell antenna structures, such as illustrated in FIG. 8,the angle between the antenna arrays may be 90 degrees. Therefore, theangle between the antenna arrays in the multi-band multi-sector antennastructures 800 a-d may be 90 degrees. In a six (6) sector cell havingsix (6) multi-cell antenna structures, such as illustrated in FIG. 9,the angle between the antenna arrays may be 60-degrees. Therefore, theangle between the antenna arrays in the multi-band multi-sector antennastructures 900 a-f may be 60 degrees.

The multi-band multi-cell antenna structure may have a fixed anglebetween the first antenna array and second antenna array oralternatively the multi-band multi-cell antenna structure may have anadjustable angle between the first and second antenna arrays through anadjustable pivot 825 located on the enclosure (e.g. the Radome) at theintersection of the first and second antenna arrays.

While example embodiments have been particularly shown and described, itwill be understood by one of ordinary skill in the art that variationsin form and detail may be made therein without departing from the spiritand scope of the claims.

We claim:
 1. A multiple sector cell-site antenna comprising: a firstantenna oriented to serve a first sector, the first antenna electricallyconnected to a first transceiver group; a second antenna oriented toserve a second sector adjacent to the first sector and the secondantenna electrically connected to the first transceiver group; and asingle enclosure covering both the first antenna and the second antenna.2. The multiple sector cell-site antenna of claim 1, wherein the firsttransceiver group is integrated in the single enclosure.
 3. The multiplesector cell-site antenna of claim 1, wherein the single enclosureincludes antenna input/output ports to connect the first antenna and thesecond antenna to the first transceiver group.
 4. The multiple sectorcell-site antenna of claim 1, wherein the first antenna and the secondantenna are each an array of antenna elements.
 5. The multiple sectorcell-site antenna of claim 1, wherein the first transceiver group is aRemote Radio Head (RRH) and includes at least four ports, the firstantenna is a first dual-polarized antenna electrically connected to twoof the at least four ports, and the second antenna is a seconddual-polarized antenna electrically connected to two of the at leastfour ports.
 6. The multiple sector cell-site antenna of claim 1, whereinthe first antenna and the second antenna are each one of an array ofdual-polarized dual-slant antenna elements, an array of dual-polarizedvertical/horizontal dipole antenna elements, and an array ofdual-polarized right-hand/left-hand polarized antenna elements.
 7. Themultiple sector cell-site antenna of claim 1, wherein the singleenclosure is a radome and the first antenna and the second antenna meetto form a first corner.
 8. The multiple sector cell-site antenna ofclaim 7, further comprising: a pivot point located on the enclosure atthe first corner, the pivot point configured to adjust an angle betweenthe first antenna and the second antenna based on a number of sectors inthe cell-site.
 9. The multiple sector cell-site antenna of claim 8,wherein the pivot point is configured to incrementally adjust the anglebetween one of 120 degrees, 90 degrees and 60 degrees.
 10. A multiplesector cell-site antenna system comprising: a first multiple sectorcell-site antenna including, a first antenna oriented to serve a firstsector, the first antenna electrically connected to a first transceivergroup; a second antenna oriented to serve a second sector, the secondsector adjacent to the first sector, the second antenna electricallyconnected to the first transceiver group; and a first enclosure coveringboth the first antenna and the second antenna; and a second multiplesector cell-site antenna including, a third antenna oriented to servethe first sector, the third antenna electrically connected to a secondtransceiver group; a fourth antenna oriented to serve a third sector,the fourth antenna electrically connected to the second transceivergroup; and a second enclosure covering both the third antenna and thefourth antenna.
 11. The system of claim 10, wherein the firsttransceiver group is integrated in the first enclosure and the secondtransceiver group is integrated in the second enclosure.
 12. The systemof claim 10, wherein the first enclosure includes antenna input/outputports configured to connect the first antenna and the second antenna tothe first transceiver group, and the second enclosure includes antennainput/output ports to connect the third antenna and the fourth antennato the second transceiver group.
 13. The system of claim 10, whereineach of the antennas are an array of antenna elements.
 14. The system ofclaim 10, wherein the first multiple sector cell-site antenna and thesecond multiple sector cell-site antenna are spatially separated by adistance such that spatial diversity against fading is provided for thefirst sector.
 15. The system of claim 10, wherein the first transceivergroup is a first remote radio read (RRH) and the second transceivergroup is a second RRH and each RRH each include at least four ports, thefirst antenna is a first polarized antenna electrically connected to twoof the at least four ports of the first RRH, the second antenna is asecond polarized antenna electrically connected to two of the at leastfour ports of the first RRH, the third antenna is a third polarizedantenna electrically connected to two of the at least four ports of thesecond RRH, and the fourth antenna is a fourth polarized antennaelectrically connected to two of the at least four ports of the secondRRH.
 16. The system of claim 10, wherein the first antenna that isconnected to the first transceiver group and third antenna that isconnected to the second transceiver group together utilize antenna crossconnect to provide redundancy and diversity to the first sector.
 17. Thesystem of claim 10, wherein the first antenna and second antenna meet toform a first corner and the third antenna and fourth antenna meet toform a second corner, and the first enclosure includes, a first pivotpoint at the first corner, the first pivot point configured to adjust anangle between the first antenna and the second antenna based on a numberof sectors in the cell-site, and the second enclosure includes a secondpivot point at the second corner, the second pivot point configured toadjust an angle between the third antenna and the fourth antenna basedon the number of sectors in the cell-site.
 18. A multiple-bandmultiple-sector cell-site antenna comprising: a first high-band antennaconfigured to utilize a first radio wave band and oriented to serve afirst sector, the first high-band antenna electrically connected to afirst high-band transceiver group; a second high-band antenna configuredto utilize the first radio wave band and oriented to serve a secondsector adjacent to the first sector, the second high-band antennaelectrically connected to the first high-band transceiver group; a firstlow-band antenna configured to utilize a low radio wave band andoriented to serve the first sector, the low-band antenna electricallyconnected to a low-band transceiver group; and a single enclosurecovering the first high-band antenna, the second high-band antenna, andthe first low-band antenna.
 19. The multiple-sector cell-site antenna ofclaim 18, wherein each of the antennas are an array of dual-polarizedantenna elements that provide two-way diversity for at least one ofuplink reception of signals and downlink transmission of signals.